Fresh water flush design

[Brad Arrington]

I’m considering how to install a fresh water flush system on my boat to both flush the system, as well as help winterize. I made up a draft diagram – are there any obvious errors?

Some details:

Designed so I can simply attach the fresh water hose and run the engines to flush.
Engines would be flushed regularly; AC included mainly for winterization purposes.
Want to flush 3 systems: Main engine (QSB 6.7 480), Cummins Onan 7.5 kWh Genset, air conditioner system
Will install shut off valves at each location where the fresh water supply tees into the raw water. To isolate each leg, but expect to keep them normally open.
Fresh water supply: considering using 3/4 inch PEX. To use bronze tees for connection to the the raw water hoses.
Water connection would be of the type normally used for city water connection to a boat. It has a backflow preventer and is pressure regulated. I can install one in the bulkhead of the cockpit.

Topic

[Dave Weber]

Hi Brad

I remember seeing one on youtube a guy did on a 6bta, really neat but simple design. Just search 6bta fresh water flush and you should see it. If I recall correctly he removed a plug on the sea water pump and piped up his inlet with valve in to the pump.

Good Luck

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Brad Arrington

[Brian Katz]

I see the issue.

[Brad Arrington]

Rob Schepis wrote:

What model strainer? You may be able to purchase replacement bronze caps.

Also, have you seen these? https://www.amazon.com/Trac-Ecological-Flushing-F-groco-1000-1250/dp/B01C04HAN8

Thanks. I saw those types and did consider them. My thinking for the pressure regulating one is that it it includes a check valve to protect both the water supply from back flow and prevent raw water from flowing out when the cap is off.

The model I’m considering allows up to 65 psi (some reduce to 45 psi – too low for this application). I’m not sure that my dock water is much more than that anyway?

[Rob Schepis]

What model strainer? You may be able to purchase replacement bronze caps.

Also, have you seen these? https://www.amazon.com/Trac-Ecological-Flushing-F-groco-1000-1250/dp/B01C04HAN8

[Brad Arrington]

Brian Katz wrote:

I’d drill and tap the tops of the strainers and forget about the tees.

I have Groco strainers with screw-on plastic tops. Seems like a risky proposition to drill and tap the plastic. I’d rather not compromise the material by trying to tap it. I’d also think it would be difficult to unscrew the lid with a water line attached it?

[Rob Schepis]

Water Inlet Connection

I’d go with a simple water connection like this one, you want everything that garden hose supply has to offer..

1 user thanked author for this post.

Brad Arrington

[Brian Katz]

I’d drill and tap the tops of the strainers and forget about the tees.

[Author]

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